title: Hypofrontality in schizophrenia: influence of normalization methods.
abstract: 1. Studies with Single Photon Emission Computed Tomography (SPECT) in schizophrenia research have utilized different approaches to normalization of data, such as cerebellar ratio and whole brain ratio methods, leading to conflicting findings. 2. The authors compared these two methods to test the hypofrontality hypothesis of schizophrenia. 3. Eighteen chronic and medicated DSM-IV schizophrenic patients and 10 healthy controls underwent two SPECT examinations using 99mTc HMPAO as a tracer at baseline and during frontal activation while applying the Wisconsin Card Sorting Test. 4. The hypofrontality hypothesis was supported with both indexes of relative perfusion, although the whole brain ratio method appeared to be more reliable and specific than the cerebellar ratio method. 5. Further studies are required to confirm these preliminary results on the specificity and sensitivity of both methods.
authors.affiliation: Hospital Universitario de Canarias, Santa Cruz de Tenerife, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Gracia Marco
authors.forename: E J
authors.initials: EJ
authors.lastname: Aguilar Garcia-Iturrospe
authors.forename: L
authors.initials: L
authors.lastname: Fernandez Lopez
authors.forename: M R
authors.initials: MR
authors.lastname: Cejas Mendez
authors.forename: O
authors.initials: O
authors.lastname: Herreros Rodriguez
authors.forename: A
authors.initials: A
authors.lastname: Diaz Ramirez
authors.forename: J
authors.initials: J
authors.lastname: Hernandez Martinez
authors.forename: M S
authors.initials: MS
authors.lastname: Keshavan
mesh_terms: D000293:Adolescent; D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D012016:Reference Values; D012559:Schizophrenia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon